A joint (not a very good one)

A hinge (from the same book)

These both refer to the same part of a hardback book, the bit between the edge of the boards and the spine, allowing the binding to flex open. Viewed from the outside it is the joint: from the inside it’s the hinge. Go figure.

I don’t know this, but I wonder if this is another of these jargon quirks which originate from the language spoken in different departments of the print works — like signature/section.

The mechanism of the hinge originates as a part of the rounding and backing process, where the edges of the book block are splayed outward under roller pressure to create lips on either side of the spine.

This illustration comes from Hugh Williamson’s Methods of Book Design, Third Edition 1983, Yale University Press. A good book, and a good man. You can see rounding and backing being done manually in the video at the rounding and backing link above.

 

 

 

The shoulder created by rounding and backing will fit into that bit of the case without any board stuck to it: the black bit between the grey boards in the picture below. Without the board it is obviously flexible enough to bend around the jutting edges.

Before anyone starts correcting others, I should perhaps say that just like all technical jargon, hinge/joint usage may vary from plant to plant. I should perhaps also add that book binders, under pressure from publishers, have steadily cut costs by compromising on details. The profile of a trade hardback book today may tend to look more like the center drawing, maybe even the one on the left!